Sustainable tilapia production in a backyard system for rural areas using fish by-products in formulated diets

Abstract

The aim of the present study was to demonstrate the feasibility of producing Tilapia (Oreochromis niloticuss, L.) with formulated diets containing acid fish silage made with Hancock (Pterigoplichthys multiradiatus) by-products in substitution of fishmeal. Thus four treatments containing increasing levels (0, 5, 10 and 15%) of acid fish silage to substitute fishmeal were used to feed tilapia juveniles in triplicate groups (average 1.5±0.7 g and 4.3±1.0 cm). Fish silage was prepared by adding citric and phosphoric acids at 2.6% each resulting in a liquefaction of the chop by-product mixture. After two weeks, the diets were prepared to contain 32-35% protein content. After 50 days of experimental period a total growth increase up to 827% was observed without significant differences among treatments. A specific growth rate from 3.70 to 4.10 and a survival rate from 96 to 99% was observed. The cost analysis shows a saving on production cost up to 23.87% using the highest incorporation level of fish silage. The use of Aquaculture Recirculation System made with components normally found in a hardware store in rural or semi urban areas is discussed. It is concluded that fish offal shows a promising activity that favors the increase in fish protein production to resolve the demand of cheap protein.